I am also old school (film for years and years) Back then I shot 20 or 24 ex instead of 36 ex , because I felt better with my vacation or job on more rolls of film (just in case) . I also had processed the odd number of rolls one time and the even number rolls at another time. I did "lose" a few rolls over the years. So I guess I believe in some sort of back up. Now with the D800, I use CF card for RAW and the SD card for jpeg. I use the SD card for not only backup, but to view on my iPad.